[Ultrastructural characteristics of experimental tumors of the intestine].

Tumors of the rat large intestine induced by subcutaneous injection of 1,2-dimethylhydrazine were studied by the method of electron microscopy. Adenocarcinomas retained histiotypical differentiation and at the same time consisted mostly of cells with a low rate of differentiation. Just on the contrary, in mucous and signet-ring cell carcinomas the picture of an advanced cell differentiation was observed in a complete loss of organogeny. The greatest malignancy of neoplasms (signet-ring carcinoma), which cells are characterized by a high degree of cytological differentiation, is a manifestation of independence of tumor progression signs.